id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35732	Postgresql Concat using || and Trigram similarity operator precedence bug	Gastón Avila		"A change from 5.0.8 to 5.1 raised a test failure in one of our queries that combines Concat with TrigramSimilarity. @emicuencac tracked this down to a recently deployed simplification on how Concat is rendered to sql here #34955 which leads to the pipe operator not being wrapped in parenthesis which were implicit when using CONCAT(...).
Here is a more explicit example
{{{
    Model.objects
        .annotate(
            concat_result=Concat(F(""field""), V(""tew"")),
            similarity=TrigramSimilarity(""concat_result"", search_term),
        )
        .filter(concat_result__trigram_similar=search_term)
        .values(""field""),
        [{""field"": ""Matthew""}],
}}}
which works well with django 5.0.8 but fails in 5.1. It fails because the mentioned change renders CONCAT using the `||` operator without wrapping parenthesis and ends up sending something like this to the DB
which would render this before the change
{{{
WHERE CONCAT('something', 'other_word') % 'search_term'
}}}
but now renders
{{{
WHERE 'something' || 'other_word' % 'search_term'
}}}
which breaks the query because the similarity operator is evaluated first.

The error that looks like this
{{{
    def execute(
        self,
        query: Query,
        params: Params | None = None,
        *,
        prepare: bool | None = None,
        binary: bool | None = None,
    ) -> Self:
        """"""
        Execute a query or command to the database.
        """"""
        try:
            with self._conn.lock:
                self._conn.wait(
                    self._execute_gen(query, params, prepare=prepare, binary=binary)
                )
        except e._NO_TRACEBACK as ex:
>           raise ex.with_traceback(None)
E           django.db.utils.ProgrammingError: argument of WHERE must be type boolean, not type text
E           LINE 1: ...e"" FROM ""suggest_vins_makemodelsearchentry"" WHERE COALESCE(""...
}}}"	Bug	new	contrib.postgres	5.1	Release blocker			Gastón Avila	Accepted	1	0	0	0	0	0